The present invention relates to poultry vaccinations. More specifically, the present invention relates to vaccines against infectious bursal disease virus (IBDV).
Vaccines which stimulate the mucosal immune system can be used to immunize, generally via an oral route, hosts against pathogens that are transmitted via the gastrointestinal, respiratory and urogenital tracts. These vaccines stimulate the mucosal immune system. See for example Shalaby, xe2x80x9cDevelopment of oral: vaccines to stimulate mucosal and systemic immunity: barriers and novel strategiesxe2x80x9d Clin Immunol Immunopathol 74(2):127-134, 1995; Mestecky et al, xe2x80x9cMucosal immunity and strategies for novel microbial vaccinesxe2x80x9d Acto Paediatr Jpn, 36(5):53744, 1994; U.S. Pat. Nos. 5,518,725 and 5,417,986.
The mucosal immune system operates through the mucosa-related IgA and a complement of T cells with mucosa-specific regulatory or effector properties and provides for host defense at the mucosal surfaces. For a more complete review of the mucosal immune system see Strober and James, xe2x80x9cThe Mucosal Immune Systemxe2x80x9d In Basic and Clinical Immunology 8th Edition eds Stites, Terr, Parslow, (Appleton and Lange, 1994), pgs 541-551, incorporated by reference in its entirety.
Infectious Bursal Disease (IBD) is a widespread disease in poultry. It is caused by a virus, which belongs to a recognized family Birnaviridae. IBD virus attacks the young bird""s immune system and causes severe illness, usually around 4-6 weeks of age. Symptoms include depression, diarrhea, muscular hemorrhage, necrosis of the bursa and sever damage to the immune system. Mortality of infected birds is high and survivors exhibit slow growth and high susceptibility to other infectious diseases. Several vaccines are available and others have been attempted as detailed in the prior art. The costs of these vaccines make it impractical to use them, particularly in developing parts of the world. In addition, several of the vaccines require sophisticated storage and administration, which again possesses problems for use in many parts of the world. Another problem with the conventional vaccines (attenuated or killed viruses) is the possibility of reconstitution of virulence of the immunizing agents. It is therefore an object of this invention to produce safe and inexpensive vaccine, which can be produced in cells of E. coli and administered by injection or orally.
Infectious Bursal Disease (IBV) is widespread and caused by IBD Virus (IBDV). Chickens with the virus present with symptoms of diarrhea, muscular hemorrhage, necrosis of the bursa of Fabricius and severe immune system damage. Mortality is high and surviving chickens exhibit growth retardation and disease susceptibility. There are several vaccines available and other have been attempted.
However, as set forth previously, the costs of these vaccines make it impractical to use them, particularly in developing parts of the world. In addition several of the vaccines require sophisticated storage and administration which again poses problems for use in many parts of the world.
It is therefore an object of this invention to produce a vaccine which stimulates the mucosal immune system and which can be administered orally and which is inexpensive and easy to use.
According to the present: invention, there is provided a stable vaccine for providing protection against disease having viral proteins transgenically expressed in plant cells. Also provided is a stable vaccine which provides protection against disease containing viral protein and coding sequences cloned into an E. coli expression system. A method of vaccination by transgenically expressing viral proteins capable of providing protection against disease into plant cells and administering the plant cells to an animal in need of vaccination is also provided. Also provided is a method of vaccination by cloning viral protein and coding sequences capable of providing protection against disease into an E. coli expression system and administering the E. coli into the animal in need of vaccination.